diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index afe5f8c..efaa733 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -5,6 +5,7 @@ idf_component_register(SRCS
     "assets/fonts/material_webfont/material_webfont_32.c"
     "main.c"
     "helper/helper_wifi.c"
+    "impl/impl_btn.c"
     "impl/impl_epd.c"
     "impl/impl_lvgl.c"
     "interface/if_standby.c"
diff --git a/main/impl/impl_btn.c b/main/impl/impl_btn.c
index e69de29..44a90e6 100644
--- a/main/impl/impl_btn.c
+++ b/main/impl/impl_btn.c
@@ -0,0 +1,35 @@
+#include "impl_btn.h"
+
+#include "driver/gpio.h"
+
+#define BTN_GPIO_1 GPIO_NUM_46
+#define BTN_GPIO_2 GPIO_NUM_45
+#define BTN_GPIO_3 GPIO_NUM_42
+#define BTN_GPIO_4 GPIO_NUM_41
+
+static void impl_btn_setup_pin(gpio_num_t pin) {
+    gpio_reset_pin(pin);
+    gpio_set_direction(pin, GPIO_MODE_INPUT);
+    gpio_pullup_en(pin);
+}
+
+esp_err_t impl_btn_init(void) {
+    impl_btn_setup_pin(BTN_GPIO_1);
+    impl_btn_setup_pin(BTN_GPIO_2);
+    impl_btn_setup_pin(BTN_GPIO_3);
+    impl_btn_setup_pin(BTN_GPIO_4);
+
+    return ESP_OK;
+}
+
+esp_err_t impl_btn_read(uint8_t *btn_status) {
+    *btn_status = 0U;
+
+    /* Bug workaround: GPIO46 cannot pull up. */
+    //if (gpio_get_level(BTN_GPIO_1) == 0) *btn_status |= 0x01U;
+    if (gpio_get_level(BTN_GPIO_2) == 0) *btn_status |= (0x01U << 1U);
+    if (gpio_get_level(BTN_GPIO_3) == 0) *btn_status |= (0x01U << 2U);
+    if (gpio_get_level(BTN_GPIO_4) == 0) *btn_status |= (0x01U << 3U);
+
+    return ESP_OK;
+}
\ No newline at end of file
diff --git a/main/impl/impl_btn.h b/main/impl/impl_btn.h
new file mode 100644
index 0000000..2049d2f
--- /dev/null
+++ b/main/impl/impl_btn.h
@@ -0,0 +1,9 @@
+#ifndef IMPL_BTN_H
+#define IMPL_BTN_H
+
+#include "esp_system.h"
+
+esp_err_t impl_btn_init(void);
+esp_err_t impl_btn_read(uint8_t *btn_status);
+
+#endif
\ No newline at end of file
diff --git a/main/impl/impl_lvgl.c b/main/impl/impl_lvgl.c
index b0e551f..f5826bc 100644
--- a/main/impl/impl_lvgl.c
+++ b/main/impl/impl_lvgl.c
@@ -1,6 +1,7 @@
 #include "impl_lvgl.h"
 
 #include "esp_log.h"
+#include "impl_btn.h"
 #include "impl_epd.h"
 
 #define LOG_TAG                 "IMPL_LVGL"
@@ -9,7 +10,7 @@
 #define EPD_DISPLAY_FRAME_SIZE  (EPD_DISPLAY_PIXEL_COUNT * 2 / 8)
 
 #define EPD_DISPLAY_GS          0
-#define EPD_DISPLAY_MAX_PARTIAL 6
+#define EPD_DISPLAY_MAX_PARTIAL 12
 
 static impl_epd_handle_t s_epd_impl;
 
@@ -34,9 +35,12 @@ static epd_gdew042t2_t s_gd_epd = {
 static uint8_t s_epd_partial_counter = 0;
 #endif
 
+static uint32_t s_last_key = 0;
+
 static lv_disp_draw_buf_t s_disp_buf;
 static lv_color_t         s_disp_store[EPD_DISPLAY_FRAME_SIZE];
 static lv_disp_drv_t      s_disp_drv;
+static lv_indev_drv_t     s_indev_drv;
 
 static TaskHandle_t      s_lv_tick_handle;
 static TaskHandle_t      s_lv_task_handle;
@@ -118,6 +122,34 @@ static void impl_lvgl_epd_rounder_cb(lv_disp_drv_t *disp_drv, lv_area_t *area) {
     area->x2 = 399;
 }
 
+static void impl_lvgl_button_read(lv_indev_drv_t *drv, lv_indev_data_t *data) {
+    uint8_t btn = 0U;
+    impl_btn_read(&btn);
+
+    if (btn != 0) {
+        switch (btn) {
+            case 0x02:
+                data->key = LV_KEY_ENTER;
+                break;
+            case 0x04:
+                data->key = LV_KEY_NEXT;
+                break;
+            case 0x08:
+                data->key = LV_KEY_PREV;
+                break;
+        }
+
+        data->state = LV_INDEV_STATE_PRESSED;
+        s_last_key  = data->key;
+    }
+
+    else {
+        data->key = s_last_key;
+        data->state  = LV_INDEV_STATE_RELEASED;
+        s_last_key   = 0U;
+    }
+}
+
 static void impl_lvgl_log_cb(const char *buf) {
     // Log to console.
     ESP_LOGI("LVGL", "%s", buf);
@@ -179,6 +211,22 @@ esp_err_t impl_lvgl_init(void) {
         return ESP_FAIL;
     }
 
+    impl_btn_init();
+
+    lv_indev_drv_init(&s_indev_drv);
+    s_indev_drv.type = LV_INDEV_TYPE_KEYPAD;
+    s_indev_drv.read_cb = impl_lvgl_button_read;
+
+    lv_indev_t *indev = lv_indev_drv_register(&s_indev_drv);
+    if(indev == NULL) {
+        ESP_LOGE(LOG_TAG, "LVGL indev register failed.");
+        return ESP_FAIL;
+    }
+
+    lv_group_t *indev_group = lv_group_create();
+    lv_group_set_default(indev_group);
+    lv_indev_set_group(indev, indev_group);
+
     lv_theme_t *default_theme = lv_theme_mono_init(disp, false, &lv_font_unscii_16);
     lv_disp_set_theme(disp, default_theme);
 
@@ -190,7 +238,7 @@ esp_err_t impl_lvgl_init(void) {
 
     xSemaphoreGive(s_lv_semphr_handle);
 
-    if (xTaskCreate(impl_lvgl_tick_task, "LV_TICK", 1024, NULL, 5, &s_lv_tick_handle) != pdPASS) {
+    if (xTaskCreate(impl_lvgl_tick_task, "LV_TICK", 4096, NULL, 5, &s_lv_tick_handle) != pdPASS) {
         ESP_LOGE(LOG_TAG, "LVGL tick task creation failed.");
         return ESP_FAIL;
     }
diff --git a/main/interface/if_standby.c b/main/interface/if_standby.c
index cf6a273..f089737 100644
--- a/main/interface/if_standby.c
+++ b/main/interface/if_standby.c
@@ -16,17 +16,27 @@ lv_obj_t *g_standby_screen;
 void if_standby_task(void *pvParameters) {
     impl_lvgl_lock();
 
+    // Custom style.
+    lv_style_t container_style;
+    lv_style_init(&container_style);
+    lv_style_set_border_color(&container_style, lv_color_white());
+    lv_style_set_border_width(&container_style, 0);
+    lv_style_set_outline_width(&container_style, 0);
+    lv_style_set_pad_all(&container_style, 0);
+
     // 1st line
     lv_obj_t *top_container = lv_obj_create(g_standby_screen);
 
-    lv_obj_set_size(top_container, 400, 60);
+    lv_obj_add_style(top_container, &container_style, 0);
+
+    lv_obj_set_size(top_container, 400, 50);
     lv_obj_align(top_container, LV_ALIGN_TOP_MID, 0, 0);
     lv_obj_set_flex_flow(top_container, LV_FLEX_FLOW_ROW);
 
-    lv_obj_t *network_status_obj = lv_obj_create(top_container);
+    lv_obj_t *network_status_obj = lv_btn_create(top_container);
     lv_obj_t *weekday_obj        = lv_obj_create(top_container);
     lv_obj_t *date_obj           = lv_obj_create(top_container);
-    lv_obj_t *battery_obj        = lv_obj_create(top_container);
+    lv_obj_t *battery_obj        = lv_btn_create(top_container);
 
     lv_obj_set_size(network_status_obj, 50, 50);
     lv_obj_set_size(battery_obj, 50, 50);
@@ -40,19 +50,23 @@ void if_standby_task(void *pvParameters) {
     // 2nd line
     lv_obj_t *main_container = lv_obj_create(g_standby_screen);
 
-    lv_obj_set_size(main_container, 400, 235);
+    lv_obj_add_style(main_container, &container_style, 0);
+
+    lv_obj_set_size(main_container, 400, 245);
     lv_obj_align_to(main_container, top_container, LV_ALIGN_OUT_BOTTOM_MID, 0, 5);
     lv_obj_set_flex_flow(main_container, LV_FLEX_FLOW_ROW);
 
     lv_obj_t *time_obj = lv_obj_create(main_container);
 
-    lv_obj_set_height(time_obj, 225);
+    lv_obj_set_height(time_obj, 245);
     lv_obj_set_flex_grow(time_obj, 1);
 
     // 2nd line, DHT column
     lv_obj_t *dht_container = lv_obj_create(main_container);
 
-    lv_obj_set_size(dht_container, 110, 225);
+    lv_obj_add_style(dht_container, &container_style, 0);
+
+    lv_obj_set_size(dht_container, 100, 245);
     lv_obj_set_flex_flow(dht_container, LV_FLEX_FLOW_COLUMN);
 
     lv_obj_t *temp_obj  = lv_obj_create(dht_container);
@@ -85,7 +99,6 @@ void if_standby_task(void *pvParameters) {
     lv_obj_set_style_text_font(humid_icon_label, &material_webfont_32, 0);
     lv_obj_set_style_text_font(humid_label, &bebas_neue_32, 0);
 
-
     lv_label_set_text(network_status_label, "\U000F092D");
     lv_label_set_text(battery_label, "\U000F007A");
     lv_label_set_text(weekday_label, "SUN");
@@ -108,13 +121,11 @@ void if_standby_task(void *pvParameters) {
 
     impl_lvgl_unlock();
 
-    struct timeval  tv;
-    struct timezone tz;
+    ESP_LOGI(LOG_TAG, "Standby screen created.");
 
     for (;;) {
-        gettimeofday(&tv, &tz);
-
-        vTaskDelay(pdMS_TO_TICKS(1000));
+        // Wait for notifications.
+        vTaskSuspend(NULL);
     }
 }
 
@@ -124,7 +135,7 @@ esp_err_t if_standby_init(void) {
     lv_disp_load_scr(g_standby_screen);
     impl_lvgl_unlock();
 
-    if (xTaskCreate(if_standby_task, "STBY_TASK", 1024, NULL, 6, &s_if_standby_handle) != pdPASS) {
+    if (xTaskCreate(if_standby_task, "STBY_TASK", 4096, NULL, 6, &s_if_standby_handle) != pdPASS) {
         return ESP_FAIL;
     }
 
diff --git a/main/lib/ltc2941/.gitkeep b/main/lib/ltc2941/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/main/lib/lv_conf.h b/main/lib/lv_conf.h
index acfb759..81f17ce 100644
--- a/main/lib/lv_conf.h
+++ b/main/lib/lv_conf.h
@@ -181,7 +181,7 @@ e.g. "stm32f769xx.h" or "stm32f429xx.h"*/
  *LV_LOG_LEVEL_ERROR       Only critical issue, when the system may fail
  *LV_LOG_LEVEL_USER        Only logs added by the user
  *LV_LOG_LEVEL_NONE        Do not log anything*/
-#  define LV_LOG_LEVEL LV_LOG_LEVEL_WARN
+#  define LV_LOG_LEVEL LV_LOG_LEVEL_INFO
 
 /*1: Print the log with 'printf';
  *0: User need to register a callback with `lv_log_register_print_cb()`*/
diff --git a/main/main.c b/main/main.c
index 7ffbdd7..f7ce66d 100644
--- a/main/main.c
+++ b/main/main.c
@@ -36,6 +36,6 @@ void app_main(void) {
 
     /* Dead loop */
     for (;;) {
-        vTaskDelay(pdMS_TO_TICKS(60000));
+        vTaskSuspend(NULL);
     }
 }